Fix & improve metainfo

[lorduskordus]

Hello again!

I noticed that on Flathub and in app stores, the description falls back to English instead of being localized to Czech. There was nothing wrong with the translation, so I checked the validation of the metainfo file and the commit history.

Validation (before fix)

appstreamcli validate --pedantic com.vkhitrin.cosmicding.metainfo.xml

I: com.vkhitrin.cosmicding:21: description-first-para-too-short
     A client to manage your bookmarks.
E: com.vkhitrin.cosmicding:30: description-enum-item-invalid ul
I: com.vkhitrin.cosmicding:130: relation-control-in-requires
I: com.vkhitrin.cosmicding:131: relation-control-in-requires

✘ Validation failed: errors: 1, infos: 3

The validator complains that there is an invalid ul element inside the description. You removed that in commit c446b8e, but then your changes got overwritten later in 5ed5dd3

I fixed the metainfo validation (based on your commit c446b8e). I'm not sure whether this will fix the localization problem, but it should as there is absolutely no other reason

Validation (after fix)

appstreamcli validate --pedantic com.vkhitrin.cosmicding.metainfo.xml

I: com.vkhitrin.cosmicding:21: description-first-para-too-short
     A client to manage your bookmarks.
I: com.vkhitrin.cosmicding:128: relation-control-in-requires
I: com.vkhitrin.cosmicding:129: relation-control-in-requires

✔ Validation was successful: infos: 3

Additionally

• I improved style by removing unnecessary dots from the listed functions under description and editing the "Support remote bookmarks providers" sentence to sound more natural
• I improved Czech translation of the metainfo

[lorduskordus]

@vkhitrin